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2606.07143 2026-06-08 math.CA math.DS math.FA math.MG math.PR 新提交

Fourier restriction estimates based on $L^q$-dimensions: beyond Stein--Tomas

基于 $L^q$ 维数的傅里叶限制估计:超越 Stein--Tomas

Marc Carnovale, Jonathan M. Fraser, Ana E. de Orellana

AI总结 本文提出一种新的傅里叶限制定理,用 $L^q$ 维数替代 Frostman 条件,得到连续范围的估计,在端点恢复 Stein--Tomas 结果,并部分解决 Bak 和 Seeger 的问题。

Comments 18 pages, 4 figures

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AI中文摘要

著名的 Stein--Tomas 限制定理给出了球面上曲面测度 $L^p\to L^2$ 限制估计成立的 $p$ 的精确范围。Mockenhaupt、Mitsis 以及 Bak--Seeger 将其推广到满足特定傅里叶衰减和 Frostman 条件的任意测度,最一般版本现已成为调和分析的基本结果。Frostman 条件本质上要求对小球的测度进行一致控制,它是描述测度局部波动的一系列更精细条件的端点。这种分析引出了测度的 $L^q$ 维数,它是分形几何的核心概念,也是多重分形分析和大偏差理论的关键工具。本文证明了新的傅里叶限制定理,使用 $L^q$ 维数代替 Frostman 条件,从而提供了一系列连续的估计,并在端点恢复了 Stein--Tomas 结果。我们的证明通过 Stein 的复插值给出了所有 $q\in(1,\infty]$ 的端点估计。特别地,在 $q=\infty$ 情形下,这部分解决了 Bak 和 Seeger 提出的问题。我们探讨了定理何时优于 Stein--Tomas,即范围不在 $q=\infty$ 处达到最优,并表明这相当普遍,包括某些 Mandelbrot 级联测度和具有多重分形行为的测度。在证明主要定理的过程中,我们基于某些卷积范数得到了 $L^q$ 维数的新描述,这本身可能具有独立意义。

英文摘要

The well-known Stein--Tomas restriction theorem gives the sharp range of $p$ for which $L^p\to L^2$ restriction estimates hold for the surface measure on the sphere. This was generalised to arbitrary measures satisfying certain Fourier decay and Frostman conditions by Mockenhaupt, Mitsis, and Bak--Seeger, with the most general version now a fundamental result in harmonic analysis. The Frostman condition essentially asks for uniform control on the measure of small balls and is the endpoint of a continuum of more nuanced conditions which describe the local fluctuations of the measure. This analysis gives rise to the $L^q$-dimensions of a measure and these are a central concept in fractal geometry and a crucial tool in multifractal analysis and the theory of large deviations. In this paper we prove a new Fourier restriction theorem which uses the $L^q$-dimensions instead of the Frostman condition, thus providing a continuum of estimates which recover Stein--Tomas at the endpoint. Our proof gives the endpoint estimate for all values of $q\in(1,\infty]$ via Stein's complex interpolation. In particular, in the case $q=\infty$ this partially resolves a question raised by Bak and Seeger. We explore when our theorem improves on Stein--Tomas, that is, when the range is not optimised at $q=\infty$, and show that this is the case quite generally, including for certain Mandelbrot cascade measures and measures with multifractal behaviour. On the way to proving our main theorem we obtain a novel description of the $L^q$-dimensions based on certain convolution norms, which may be of interest in its own right.

2606.07142 2026-06-08 math.AG math.AC math.CO math.KT 新提交

Polyhedral models for K-theory of toric and flag varieties

环面和旗簇的K-理论的多面体模型

Leonid Monin, Evgeny Smirnov

AI总结 将Pukhlikov-Khovanskii型表示推广到环面和旗簇的K-理论,通过构造与线性多面体族相关的K-环,并证明其可实现为相应簇的K-理论。

Comments 26 pages; comments welcome

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AI中文摘要

1992年,Pukhlikov和Khovanskii将环面簇的上同调环描述为虚拟多面体空间上微分算子环的商。后来Kaveh将此构造推广到全旗簇的上同调环情形。本文中,我们将Pukhlikov-Khovanskii型表示推广到环面和旗簇的K-理论情形。首先,我们研究作为自由阿贝尔群(可能无限秩)群代数商的Frobenius代数。然后,我们应用此构造来定义与(虚拟)多面体的线性族相关联的K-环。我们详细研究了此类族的两个例子:具有固定法扇的整数(虚拟)多面体族和(虚拟)Gelfand-Zetlin多面体族。我们证明了环面和旗簇的K-理论可以实现为上述族的K-环,并由此得到这些K-环中的自然关系集。此外,我们描述了环面轨道闭包和A型旗簇中Schubert簇的结构层的类。最后,我们证明了我们的结果在T-等变设定下也成立。

英文摘要

In 1992, Pukhlikov and Khovanskii provided a description of the cohomology ring of toric variety as a quotient of the ring of differential operators on spaces of virtual polytopes. Later Kaveh generalized this construction to the case of cohomology rings for full flag varieties. In this paper we extend Pukhlikov-Khovanskii type presentation to the case of K-theory of toric and flag varieties. First, we study the Frobenius algebras obtained as quotients of the group algebra of free abelian group (possibly of infinite rank). Then we apply this construction to define a K-ring associated to a linear family of (virtual) polytopes. We study in detail two examples of such families: the family of integer (virtual) polytopes with a fixed normal fan and the family of (virtual) Gelfand-Zetlin polytopes. We show that the K-theory of toric and flag varieties can be realized as K-rings of the above families and use this to get natural set of relations in the above K-rings. Further, we describe the classes of structure sheaves of toric orbit closures and Schubert varieties in type A flag varieties. Finally, we show that our results also hold true in T-equivariant setting.

2606.07139 2026-06-08 math.NT math.CA math.DS 新提交

Multi-scale properties of continued fraction sets

连分数集合的多尺度性质

Alex Rutar

AI总结 本文综述了限制连分数展开数字来自非空子集D⊂N的实数集的维数理论,涵盖Hausdorff维数、盒维数等,并讨论相关开问题。

Comments 33 pages, 2 figures. Overview article based on arXiv:2406.12821 prepared for minicourse at the Simons semester on continued fractions at IMPAN, Warsaw, in 2026

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AI中文摘要

我们综述了具有正则连分数展开且展开数字限制在非空(可能无限)子集$\mathcal{D}\subset\mathbb{N}$中的实数集的维数理论。我们回顾了Hausdorff维数、盒维数以及这些集合的其它分形维数的已知结果,并讨论了一些相关的开问题。

英文摘要

We survey the dimension theory of sets of real numbers with regular continued fraction expansion restricted to a non-empty and possibly infinite subset $\mathcal{D}\subset\mathbb{N}$.

2606.07136 2026-06-08 math.QA math.RT 新提交

On a Small Version of the Reflection Equation Algebra

关于反射方程代数的小版本

Stephen T. Moore

AI总结 本文给出了与GL_N在奇偶单位根处相关的小反射方程代数的另一种表示,并利用该表示分类了其不可约表示,随后推广到一族代数并应用于U_q(sl_N)融合范畴的模范畴研究。

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AI中文摘要

我们给出了与$GL_N$在奇偶单位根处相关的小反射方程代数的另一种表示,并利用我们的表示分类了其不可约表示。然后我们描述了一族推广小反射方程代数的代数,并考虑了它们在$U_q(sl_N)$融合范畴上的模范畴研究中的应用。

英文摘要

We give an alternative presentation of the small version of the reflection equation algebra associated to $GL_N$ at both odd and even roots of unity, and use our presentation to classify its irreducible representations. We then describe a family of algebras generalizing the small reflection equation algebra, and consider their application to the study of module categories over $U_q(sl_N)$ fusion categories.

2606.07126 2026-06-08 math.CO 新提交

A note on the extremal number of Berge-$C_4$

关于Berge-$C_4$极值数的一个注记

Nika Salia, Casey Tompkins

AI总结 本文改进了无Berge-$C_4$的3一致超图的极值数的上界,将领先常数从$1/\sqrt{10}$改进到$1/(2+\sqrt2)$。

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AI中文摘要

我们改进了无Berge-$C_4$的$3$-一致超图的极值数的已知上界。更精确地说,我们证明每个不含长度为四的Berge圈的$n$顶点$3$-一致超图至多有\\[ \frac{n^{3/2}}{2+\sqrt2}+O(n) \\]条超边。这将之前的最佳领先常数$1/\sqrt{10}$改进到$1/(2+\sqrt2)$。

英文摘要

We improve the known upper bound for the extremal number of Berge-$C_4$-free $3$-uniform hypergraphs. More precisely, we prove that every $n$-vertex $3$-uniform hypergraph with no Berge cycle of length four has at most \[ \frac{n^{3/2}}{2+\sqrt2}+O(n) \] hyperedges. This improves the previous best-known leading constant $1/\sqrt{10}$ to $1/(2+\sqrt2)$.

2606.07124 2026-06-08 cs.IT math.IT stat.ML 新提交

Information-Theoretic Bounds for Sparse Covariance Estimation in the Vertical-Split Distributed Model

垂直分割分布式模型中稀疏协方差估计的信息论界

Jing Yee Tan, Guangyue Han

AI总结 研究垂直分割分布式设置下稀疏协方差矩阵的极小化估计误差,证明稀疏性可降低通信和样本复杂度,并给出匹配的上下界。

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AI中文摘要

我们研究了垂直分割(特征分割)设置下分布式协方差矩阵估计的极小化估计误差,其中两个智能体各自观测 $m$ 个独立同分布的子高斯样本的不同坐标,并向中心服务器传输有限比特数。虽然 Rahmani 等人 [2025] 对稠密(无结构)互协方差矩阵建立了近乎紧的界,但我们研究了在互协方差 $C_{21}$ 上施加元素级 $s$-稀疏性是否能降低所需的通信和样本复杂度。与水平分割设置(Braverman 等人 [2016] 表明稀疏性不能降低均值估计的通信成本)相反,我们证明在垂直分割中稀疏性确实有助于互协方差估计。具体地,我们建立了极小化下界,表明每个智能体的通信预算为 $B_k = \Omega(\sigma^4 d_k\\, s' \log(d_1 d_2/s')/\varepsilon^2)$,互协方差估计的样本复杂度为 $m = \Omega(\sigma^4\\, s' \log(d_1 d_2/s')/\varepsilon^2)$,其中 $s' = s \wedge d_{\min}$。对于 $1$-稀疏情况,与稠密率相比,这实现了从 $d_1 d_2$ 到 $\log(d_1 d_2)$ 的指数级改进。我们的下界通过 Fano 方法建立,使用基于 Varshamov--Gilbert 型论证的显式稀疏打包(针对符号部分置换矩阵)并结合 Rahmani 等人 [2025] 的条件强数据处理不等式。我们通过匹配的可实现方案证明了界的紧性,该方案基于覆盖网量化和逐元素硬阈值,在多项式对数因子内达到 $s$-稀疏下界。

英文摘要

We study the minimax estimation error for distributed covariance matrix estimation in the vertical-split (feature-split) setting, where two agents each observe different coordinates of $m$ i.i.d. sub-Gaussian samples and communicate a limited number of bits to a central server. While Rahmani et al. [2025] established nearly tight bounds for dense (unstructured) cross-covariance matrices, we investigate whether imposing elementwise $s$-sparsity on the cross-covariance $C_{21}$ can reduce the required communication and sample complexity. In contrast to the horizontal-split setting, where Braverman et al. [2016] showed that sparsity does not reduce communication cost for mean estimation, we prove that sparsity does help for cross-covariance estimation in the vertical split. Specifically, we establish minimax lower bounds showing that the communication budget per agent scales as $B_k = Ω(σ^4 d_k\, s' \log(d_1 d_2/s')/\varepsilon^2)$ and the sample complexity for cross-covariance estimation as $m = Ω(σ^4\, s' \log(d_1 d_2/s')/\varepsilon^2)$, where $s' = s \wedge d_{\min}$. For the $1$-sparse case, this yields an exponential improvement from $d_1 d_2$ to $\log(d_1 d_2)$ compared to the dense rate. Our lower bounds are established via Fano's method with an explicit sparse packing using a Varshamov--Gilbert-type argument for signed partial permutation matrices combined with the Conditional Strong Data Processing Inequality of Rahmani et al. [2025]. We show the bounds are tight with a matching achievable scheme, based on covering-net quantization and entry-wise hard thresholding, that attains the $s$-sparse lower bound up to polylogarithmic factors.

2606.07122 2026-06-08 math.NA cs.NA 新提交

A Unified DeepONet Framework for Logarithmically Stable Infinite-Dimensional Inverse Problems

用于对数稳定无限维逆问题的统一DeepONet框架

Wen-Jie Wu, Tiexiang Li, Wen-Wei Lin

AI总结 提出统一DeepONet框架求解对数稳定逆问题,将逆映射分解为测量编码、神经逼近和函数重建三部分,并给出先验误差界。

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AI中文摘要

我们开发了一个统一的DeepONet框架,用于对数稳定的无限维逆问题,以逆声散射作为模型应用。该框架在算子层面制定,将学习的逆映射分解为测量编码、有限维神经逼近和函数重建组件。对于满足对数稳定性估计的逆映射,我们建立了定量的先验误差界,分别给出了编码器误差、神经逼近误差和重建误差的估计,从而表征了对编码器维度、网络大小和重建维度的依赖性。为了比较,我们还记录了由相同误差分解产生的相应Lipschitz稳定估计。然后将抽象理论专门应用于从固定频率远场测量中恢复介质对比度。二维和三维数值实验展示了在测量噪声下的稳定重建。

英文摘要

We develop a unified DeepONet framework for logarithmically stable infinite-dimensional inverse problems, with inverse acoustic scattering as a model application. The framework is formulated at the operator level by separating the learned inverse map into measurement encoding, finite-dimensional neural approximation, and functional reconstruction components. For inverse maps satisfying a logarithmic stability estimate, we establish quantitative a priori error bounds giving separate estimates for the encoder error, the neural approximation error, and the reconstruction error, thereby characterizing the dependence on the encoder dimension, the network size, and the reconstruction dimension. For comparison, we also record the corresponding Lipschitz-stable estimate arising from the same error decomposition. The abstract theory is then specialized to the recovery of a medium contrast from fixed-frequency far-field measurements. Numerical experiments in two and three dimensions illustrate stable reconstructions under measurement noise.

2606.07097 2026-06-08 math.NT 新提交

Note on the Equivalence of Costas Polynomials and Orthomorphisms

关于Costas多项式与正交映射等价性的注记

Amela Muratović-Ribić, Aleksandar Balašev-Samarski

AI总结 本文建立了Costas多项式与一类特殊正交映射之间的等价关系,并利用该等价性给出了Costas多项式数量的下界及其性质,同时展示了它们可用于构造完全互斥拉丁方族。

Comments 8 pages

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AI中文摘要

我们建立了Costas多项式的存在性与一类特殊正交映射的存在性之间的等价关系,使得它们的复合也是正交映射。在这些正交映射上进行计算更为简便。我们给出了Costas多项式数量的下界,并推导了它们的一些性质。我们证明,Costas多项式作为平面多项式的乘法模拟,也可以用于构造完全互斥拉丁方族。

英文摘要

We establish an equivalence between the existence of Costas polynomials and the existence of a special kind of orthomorphism such that their compositions are also orthomorphisms. Computations are easier over these orthomorphisms. We provide a lower bound for the number of Costas polynomials and derive some of their properties. We show that Costas polynomials, by virtue of being multiplicative analogs of planar polynomials, can also be used to construct complete families of mutually orthogonal Latin squares.

2606.07096 2026-06-08 math.PR math.AP 新提交

Non-selection of Lagrangian trajectories in the zero-noise limit for a class of stochastic regularizations

一类随机正则化在零噪声极限下拉格朗日轨迹的非选择性

Lucio Galeati, Filippo Giovagnini, Massimo Sorella

AI总结 研究证明对于由散度自由、Hölder连续向量场驱动的SDE,在零噪声极限下缺乏轨迹选择性,适用于分数布朗运动等广泛的正则化加性噪声。

Comments 35 pages, 2 figures

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AI中文摘要

我们证明了对于由散度自由、Hölder连续(指数$\alpha\in(0,1)$,任意接近但固定为$1$)向量场驱动的SDE,在零噪声极限下缺乏选择性。该结果适用于一类广泛的正则化加性噪声,包括分数布朗运动和稳定Lévy过程。证明结合了基于混合速度场确定性流分析的路径拉格朗日论证,以及来自随机缝合引理的概率估计。这证明了缺乏选择性同时发生在一个大的初始数据集上,其补集的Lebesgue测度任意小。

英文摘要

We prove the lack of selection in the zero-noise limit for solutions to SDEs driven by a divergence-free, Hölder continuous vector field with exponent $α\in(0,1)$, arbitrarily close to $1$ but fixed. The result applies to a broad class of regularizing additive noises, including fractional Brownian motion and stable Lévy processes. The proof combines pathwise Lagrangian arguments, based on the analysis of the deterministic flows associated to mixing velocity fields, with probabilistic estimates coming from the stochastic sewing lemma. This allows to show that lack of selection happens simultaneously on a large set of initial data, whose complement has arbitrarily small Lebesgue measure.

2606.07065 2026-06-08 math.ST math.PR stat.ME stat.TH 新提交

Ising Models on Inhomogeneous Random Graphs: Inference, Local Asymptotic Minimaxity, and Limit of Experiments

非均匀随机图上的伊辛模型:推断、局部渐近极小极大性和实验极限

Somabha Mukherjee, Sanchayan Bhowal, Anirban Chatterjee, Bhaswar B. Bhattacharya

AI总结 针对亚临界参数下非均匀随机图上的伊辛模型,提出一种计算高效的闭合形式估计量,证明其与极大似然估计具有相同渐近分布和方差,并建立局部渐近极小极大最优性。

Comments 82 pages, 2 figures. Abstract shortened to meet ArXiv requirements

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AI中文摘要

在本文中,我们为亚临界参数区间内非均匀随机图上的伊辛模型开发了一个具有尖锐渐近最优性保证的推断框架。我们首先基于模型的一个样本,刻画了自然参数的极大似然估计的渐近分布,覆盖了稀疏和稠密网络两种情形。接着,为克服极大似然方法的计算困难,我们通过似然方程的一步近似提出一个简单的闭合形式估计量。我们证明该估计量达到与极大似然估计相同的渐近分布和方差,从而为自然参数提供了一个计算高效且渐近有效的置信区间。我们通过建立Hájek--Le Cam型局部渐近极小极大定理来补充这些推断结果,表明所提出的估计量在真实参数的收缩邻域内,在速率和领先常数上均达到最小的渐近最大风险。我们还推导了相应的实验极限。据我们所知,这是针对网络依赖数据的首批尖锐渐近最优性结果之一。最后,我们研究了自然参数的拟合优度检验,推导了似然比检验的局部功效和极小极大检测率。我们的分析依赖于非均匀随机图上伊辛模型的充分统计量(哈密顿量)和随机配分函数的新波动结果,这些结果本身也具有独立意义。

英文摘要

In this paper, we develop an inferential framework with sharp asymptotic optimality guarantees for Ising models on inhomogeneous random graphs in the subcritical parameter regime. We begin by characterizing the asymptotic distribution of the maximum likelihood (ML) estimate of the natural parameter, based on a single sample from the underlying model, covering both sparse and dense network regimes. Next, to overcome the computational intractability of the ML method, we propose a simple closed-form estimate obtained from a one-step approximation to the likelihood equation. We show that this estimate attains the same asymptotic distribution and variance as the ML estimate, thereby yielding a computationally efficient and asymptotically valid confidence interval for the natural parameter. We complement these inferential results by establishing a Hájek--Le Cam-type local asymptotic minimax theorem, showing that the proposed estimate achieves the smallest possible asymptotic maximum risk, both in rate and in leading constant, over shrinking neighborhoods of the true parameter. We also derive the corresponding limit of experiments. To the best of our knowledge, these are among the first sharp asymptotic optimality results for network-dependent data. Finally, we study goodness-of-fit testing for the natural parameter, deriving the local power of the likelihood ratio test and minimax detection rates. Our analysis relies on new fluctuation results for the sufficient statistic (Hamiltonian) and for the random partition function of Ising models on inhomogeneous random graphs, which are of independent interest.

2606.07064 2026-06-08 math.AP 新提交

An inverse source problem for the Monge--Ampere equation from large boundary data

大边界数据下的Monge-Ampère方程反源问题

Cătălin I. Cârstea, Tuhin Ghosh

AI总结 研究有界光滑一致凸域上Monge-Ampère方程的反源问题,利用大边界值族将问题转化为X射线变换的单射性,证明Dirichlet-to-Neumann映射唯一确定正源。

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AI中文摘要

我们研究有界光滑一致凸域上Monge-Ampère方程\\[ \det D^2u=f(x) \\]的反源问题。在光滑经典框架下,我们证明与凸解相关的Dirichlet-to-Neumann映射唯一确定正源。证明使用一族大边界值,并将反源问题简化为欧几里得X射线变换的单射性。

英文摘要

We study an inverse source problem for the Monge--Ampere equation \[ \det D^2u=f(x) \] on a bounded smooth uniformly convex domain. In the smooth classical regime, we prove that the Dirichlet-to-Neumann map associated with convex solutions determines the positive source uniquely. The proof uses a family of large boundary values and reduces the inverse source problem to the injectivity of the Euclidean X-ray transform.

2606.07061 2026-06-08 math.CO 新提交

Polynomial reduction for $q$-holonomic sequences

关于 $q$-全纯序列的多项式约化

Rong-Hua Wang, Xiao-Ran Yang, Michael X. X. Zhong

AI总结 本文提出了一种针对 $q$-全纯序列的(Laurent)多项式约化方法,通过分解Laurent多项式为可求和部分和低次余项,并引入对称条件下的幂可分约化,应用于$q$-中心Delannoy数以推导新的$q$-恒等式和$q$-同余式。

Comments 23 pages

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AI中文摘要

本文提供了针对 $q$-全纯序列 $F_k(q)$ 的(Laurent)多项式约化。我们首先刻画了使得乘积 $\tilde{p}(q^k)F_k(q)$ 可求和的 Laurent 多项式 $\tilde{p}(x)$。然后给出了约化框架,将任意给定的 Laurent 多项式分解为可求和部分和次数更低的余项。最后,我们引入了对于递推关系满足某种对称条件的 $q$-全纯序列的幂可分约化。其优点在于,它不仅能同时消除满足对称条件的 Laurent 多项式的最高次项和最低次项,还能保证余项的对称性。作为应用,我们将该约化应用于 $q$-中心 Delannoy 数,推导出新的 $q$-恒等式和 $q$-同余式。

英文摘要

This paper provides a (Laurent) polynomial reduction to $q$-holonomic sequences $F_k(q)$. We first characterize Laurent polynomials $\tilde{p}(x)$ such that the product $\tilde{p}(q^k)F_k(q)$ is summable. Then the reduction framework is given to decompose any given Laurent polynomial into a summable part and a remainder with lower degree. Finally, we introduce a power-partible reduction for $q$-holonomic sequences of which the recurrence relation satisfies a certain symmetry condition. The advantage is that it can not only simultaneously eliminate the highest-degree and lowest-degree terms of a Laurent polynomial satisfying a symmetry condition, but also guarantee the symmetry of the remainder. As applications, we apply the reduction to $q$-central-Delannoy numbers to derive new $q$-identities and $q$-congruences.

2606.07055 2026-06-08 math.FA 新提交

Lacunary Series, Nonlinear Functionals and Banach Space Structure

缺项级数、非线性泛函与Banach空间结构

Istvan Berkes, Eduard Stefanescu, Robert Tichy

AI总结 研究缺项随机变量序列的非线性泛函的渐近行为,建立Aldous子序列原理的一致版本,并证明Orlicz空间中的Kadec-Pełczyński型定理。

Comments To appear in Studia Mathematica

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AI中文摘要

在之前的论文\cite{BT}中,我们研究了$L_p$中缺项随机变量序列$(X_{n_k})$的$\| \sum_{k=1}^N a_k X_{n_k}\|_p$的渐近行为,并利用该结果给出了当$1\le p<2$时Kadec-Pełczyński定理中第一种情形的充要条件。在本文中,我们将此结果推广到非线性泛函$f_k (a_1 X_{n_1}, \ldots, a_k X_{n_k})$,建立了Aldous\cite{ald}子序列原理的一致版本。此外,我们证明了Orlicz空间$L_\psi$中的Kadec-Pełczyński型定理。

英文摘要

In a previous paper \cite{BT} we studied the asymptotic behavior of $\| \sum_{k=1}^N a_k X_{n_k}\|_p$ for lacunary sequences $(X_{n_k})$ of random variables in $L_p$ and used the result to give a necessary and sufficient condition for the first alternative in the Kadec-Pełczynski theorem in the case $1\le p<2$. In the present paper we extend this result for nonlinear functionals $f_k (a_1 X_{n_1}, \ldots, a_k X_{n_k})$, establishing a uniform version of the subsequence principle of Aldous \cite{ald}. Moreover, we prove Kadec-Pełczynski type theorems in Orlicz spaces $L_ψ$.

2606.07045 2026-06-08 math.AT math.CO 新提交

Chamber Decompositions of Moment Polytopes for Torus Actions of Positive Complexity

正复杂度环面作用的矩多面体的室分解

Matvey Sergeev

AI总结 本文针对环面T^n在复Grassmann流形G_{n,2}上的标准作用,引入容许图概念,给出了容许多面体的完全归纳描述,并揭示了室分解与副扇形的联系。

Comments 20 pages, 7 figures

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AI中文摘要

本文发展了Buchstaber和Terzić关于紧环面$T^n = (S^1)^n$在复Grassmann流形$G_{n,2}$上标准作用的一系列论文的结果。在这些工作中,引入了$\mathbb{R}^n$中的一个超平面配置,该配置决定了$T^n$作用在$G_{n,2}$上的超单纯形$\Delta_{n,2}$的室分解。我们为环面$T^n$在复Grassmann流形$G_{n,2}$上的标准作用引入了容许图的概念。借助容许图,我们给出了$\Delta_{n,2}$中容许多面体以及$(\mathbb{C}^*)^n$在$G_{n,2}$上标准作用下作为$(\mathbb{C}^*)^n$轨道闭包的toric簇的完全归纳描述(关于$n \ge 4$)。我们考虑$T^n$-等变Plücker嵌入$G_{n,2} \hookrightarrow \mathbb{C}P^{N_2}$,其中$N_2 = \binom{n}{2}-1$。利用容许图,对于所考虑的$T^n$作用,我们描述了$\mathbb{R}^n$中决定$T^n$作用在$G_{n,2}$和$\mathbb{C}P^{N_2}$上的$\Delta_{n,2}$中室的超平面配置。Gel'fand、Kapranov和Zelevinsky引入了副多面体和副扇形的概念,与描述给定凸多面体三角剖分的问题相关,这密切关联于判别式和结式的Newton多面体。对于$\mathbb{C}P^{N_2}$上的$T^n$作用,我们证明了$\mathbb{R}^n$中以原点为顶点、由室张成的锥体构成了由$\Delta_{n,2}$顶点张成的锥体的副扇形。

英文摘要

The present work develops the results of the series of papers by Buchstaber and Terzić on the standard actions of the compact torus $T^n = (S^1)^n$ on the complex Grassmann manifolds $G_{n,2}$. In those works, a hyperplane arrangement in $\mathbb{R}^n$ was introduced that determines the chamber decomposition of the hypersimplex $Δ_{n,2}$ for the $T^n$-action on $G_{n,2}$. We introduce a notion of admissible graph for the standard action of the torus $T^n$ on the complex Grassmannian $G_{n,2}$. In terms of admissible graphs, we give a complete inductive description (with respect to $n \ge 4$) of the admissible polytopes in $Δ_{n,2}$, as well as of the toric varieties arising as closures of $(\mathbb{C}^*)^n$-orbits on $G_{n,2}$ under the standard $(\mathbb{C}^*)^n$-action. We consider the $T^n$-equivariant Plücker embedding $G_{n,2} \hookrightarrow \mathbb{C}P^{N_2}$, where $N_2 = \binom{n}{2}-1$. Using admissible graphs, for the considered $T^n$-actions, we describe hyperplane arrangements in $\mathbb{R}^n$ that determine the chambers in $Δ_{n,2}$ for the $T^n$-actions on $G_{n,2}$ and $\mathbb{C}P^{N_2}$. Gel'fand, Kapranov, and Zelevinsky introduced the notions of secondary polytopes and secondary fans in connection with the problem of describing triangulations of a given convex polytope, which is closely related to the Newton polytopes of discriminants and resultants. For the $T^n$-action on $\mathbb{C}P^{N_2}$, we show that the cones in $\mathbb{R}^n$ with vertex at the origin spanned by the chambers form the secondary fan of the cone spanned by the vertices of $Δ_{n,2}$.

2606.07037 2026-06-08 math.CT math.DG 新提交

Ehresmann connections in tangent categories

切触范畴中的Ehresmann联络

Geoffrey Cruttwell, Marcello Lanfranchi

AI总结 将Ehresmann联络推广到切触范畴,给出等价刻画并证明其推广Koszul联络,定义平行移动和曲率,证明结构方程和Bianchi恒等式。

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AI中文摘要

联络理论是微分几何的核心。由Levi-Civita和Christoffel发现,后经Cartan、Koszul等人研究,联络以其最一般的形式出现,称为Ehresmann联络。Ehresmann联络包括将浸没的切丛分解为垂直子丛和给定的水平分布。在本文中,我们将Ehresmann联络推广到称为切触范畴的范畴设置。切触范畴最初由Rosický于1984年引入,后由Cockett和第一作者于2014年推广,它提供了一个研究几何的范畴框架,远远超出光滑流形,包括代数几何和非交换几何。本文在切触范畴的背景下引入并研究Ehresmann联络。我们给出了完全联络和抽象联络的各种等价表述,并证明它们推广了Koszul联络。我们还定义了此类联络的平行移动和曲率,并证明了曲率的结构方程和Bianchi恒等式。

英文摘要

The theory of connections is at the very core of differential geometry. Discovered by Levi-Civita and Christoffel and later studied by Cartan, Koszul, and others, connections appear in their most general form under the name of Ehresmann connections. An Ehresmann connection consists of a splitting of the tangent bundle of a submersion into the vertical sub-bundle and a given horizontal distribution. In this paper, we generalize Ehresmann connection to a categorical setting called tangent categories. Initially introduced by Rosický in 1984 and later generalized by Cockett and the first author in 2014, tangent categories provide a categorical framework to study geometry that extends well beyond smooth manifolds, including algebraic geometry and non-commutative geometry. In this paper we introduce and study Ehresmann connections in the context of tangent categories. We give various equivalent formulations in term of full and abstract connections and prove that they generalize Koszul connections. We also define parallel transport and curvature for such connections, and prove the structural equation and the Bianchi identity for the curvature.

2606.07029 2026-06-08 math.OC 新提交

A Min-Max Gradient Search Method for Constrained Simulation Optimization

约束仿真优化的极小极大梯度搜索方法

Ruiyang Jin, Siyang Gao, Henry Lam

AI总结 提出一种单循环算法MGS,结合原始-对偶框架与随机梯度估计器,通过交替梯度上升和下降优化目标并惩罚约束违反,首次为单循环CSO算法建立有限时间收敛保证,速率为$\ ilde{O}(T^{-1/3})$。

Comments 27pages, 4figures

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AI中文摘要

约束仿真优化(CSO)是在性能约束下优化随机系统的通用框架,广泛应用于目标函数和约束评估仅能通过含噪声仿真输出获得的情况。与无约束设置相比,基于仿真的约束缺乏可解析的梯度,使得开发高效求解方法并建立非渐近保证更具挑战性。为解决这一问题,我们提出了一种新颖的单循环算法,称为极小极大梯度搜索(MGS),该算法将原始-对偶框架与随机梯度估计器相结合。与基于梯度下降求解仿真优化问题的传统随机逼近方法(如Zhou和Bhatnagar (2017)以及Hu和Fu (2025))不同,MGS对原始变量和对偶变量交替进行梯度下降和上升,从而在惩罚约束违反的同时改进目标函数。我们首次通过证明MGS以$\ ilde{O}(T^{-1/3})$的速率收敛到平稳解(在温和条件下为Karush-Kuhn-Tucker点)来建立单循环CSO算法的有限时间收敛保证,其中$T$为迭代次数。在串行排队系统和2000维优化问题上的数值实验展示了MGS的优越性能和可扩展性。

英文摘要

Constrained simulation optimization (CSO) is a general framework for optimizing stochastic systems under performance constraints. It arises widely in practice where objective and constraint evaluations are available only through noisy simulation outputs. Compared with the unconstrained setting, the lack of accessible analytical gradients for simulation-based constraints makes it more challenging to develop efficient solution methods and establish non-asymptotic guarantees. To address this gap, we propose a novel single-loop algorithm, called min-max gradient search (MGS), which integrates a primal-dual framework with stochastic gradient estimators. Unlike conventional stochastic approximation methods based on gradient descent for solving simulation optimization problems, such as Zhou and Bhatnagar (2017) and Hu and Fu (2025), MGS performs alternating gradient descent and ascent on the primal and dual variables, which improves the objective while penalizing constraint violations. For the first time, we establish a finite-time convergence guarantee for single-loop CSO algorithms by showing that MGS converges to a stationary solution (a Karush-Kuhn-Tucker point under mild conditions) at a rate of $\tilde{O}(T^{-1/3})$, where $T$ is the number of iterations. Numerical experiments on a serial queuing system and a 2000-dimensional optimization problem demonstrate the superior performance and scalability of MGS.

2606.07028 2026-06-08 math.CA math.FA 新提交

Discrepancy estimates for multi-dimensional non-smooth convex bodies: a case study

多维非光滑凸体的差异估计:一个案例研究

Roberto Bramati, Luca Brandolini, Alessandro Monguzzi

AI总结 针对环面上有限点集相对于平移和缩放的非光滑边界凸体的L^2平均差异,在傅里叶变换衰减的各向异性假设下,证明了匹配的上下界,得到速率N^{1 - (d+1)/(d^2+d-1)},并恢复d=2时的已知指数2/5。

Comments 34 pages

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AI中文摘要

我们研究了环面$\mathbb{T}^d$上有限点序列相对于具有非光滑边界的凸体的平移和缩放副本的$L^2$平均差异。在关于体傅里叶变换衰减的适当各向异性假设下,我们证明了平均差异的匹配下界和上界,得到了速率$ N^{1 - \frac{d+1}{d^2+d-1}}$。这产生了光滑凸体和多面体之间的中间状态,并恢复了维度$d=2$中已知的指数$2/5$。论证依赖于调和分析技术与适应各向异性设置的平均过程的结合。作为一个应用,我们分析了一类具有混合几何特征的凸体,包括平坦区域、弯曲部分和边缘。

英文摘要

We study $L^2$-averaged discrepancies of finite sequences of points in the torus $\mathbb{T}^d$ with respect to translated and dilated copies of convex bodies with non-smooth boundary. Under suitable anisotropic assumptions on the decay of the Fourier transform of the body, we prove matching lower and upper bounds for the averaged discrepancy, obtaining the rate $ N^{1 - \frac{d+1}{d^2+d-1}}$. This yields an intermediate regime between smooth convex bodies and polytopes and recovers the known exponent $2/5$ in dimension $d=2$. The argument relies on harmonic analysis techniques combined with averaging procedures adapted to the anisotropic setting. As an application, we analyze a class of convex bodies exhibiting mixed geometric features, including flat regions, curved parts, and edges.

2606.07025 2026-06-08 cs.IT math.IT 新提交

Environment-Division Multiple Access: an Enabler for AI-Native Multiple Access

环境分割多址接入:AI原生多址接入的使能技术

Zhiguo Ding

AI总结 提出环境分割多址接入(EDMA)技术,利用无线传播环境特性、集成先进柔性天线并主动重构传播环境,并探讨AI辅助与AI原生两种应用模式。

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AI中文摘要

本文介绍了一种新型多址接入技术——环境分割多址接入(EDMA),并阐述了其与AI原生通信网络的交互。具体而言,描述了EDMA的关键特性,如利用无线传播环境的特征、集成先进柔性天线以及主动重构传播环境。本文还说明了AI工具在多址接入中的两类应用,即AI辅助EDMA和AI原生EDMA。最后,讨论了AI辅助EDMA未来研究中的开放问题和重要方向。

英文摘要

In this article, a new type of multiple access, termed Environment-Division Multiple Access (EDMA), is introduced and its interaction with AI-native communication networks is illustrated. In particular, the key properties of EDMA, such as utilizing the features of wireless propagation environments, integrating advanced flexible antennas, and proactively reconfiguring propagation environments, are described. The article also illustrates two types of applications of AI tools to multiple access, namely AI-assisted EDMA and AI-native EDMA. Finally, open problems and important directions for future research in AI-assisted EDMA are discussed.

2606.07023 2026-06-08 math.GN 新提交

Arithmetic-geometric mean, additive, and multiplicative contractions: New generalizations of the Banach contraction principle

算术-几何平均、加法和乘法压缩:Banach压缩原理的新推广

Irom Shashikanta Singh, Yumnam Mahendra Singh, Evgeniy Petrov, Ruslan Salimov

AI总结 基于算术与几何平均之间的经典不等式,引入辅助半度量δ,定义算术-几何平均型、乘法型和加法型压缩条件,证明连续情形下的不动点定理,并给出构造性推论。

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AI中文摘要

我们基于算术与几何平均之间的经典不等式引入了新的压缩条件。通过引入辅助半度量$\delta$,定义了算术-几何平均型、乘法型和加法型压缩。发现了这些压缩类型之间的联系。在上述压缩连续的情况下证明了不动点定理。在$\delta$满足适当的正则条件(如d-正则、强d-正则或d-下有界)时,我们得到了构造性推论。构造了各种例子来证明我们的结果。表明在特定条件下,加法型映射的不动点定理等价于M. Jleli和B. Samet最近引入的扰动度量空间的不动点定理。

英文摘要

We introduce new contraction conditions based on classical inequality between arithmetic and geometric means. By incorporating an auxiliary semimetric $δ$, we define arithmetic-geometric mean, multiplicative-type, and additive-type contractions. Connections between these types of contractions are found. Fixed point theorems are proved in the case of continuity of the above mentioned contractions. Under suitable regularity conditions on $δ$ (such as being d-regular, strongly d-regular, or d-lower bounded) we obtain constructive corollaries. Various examples demonstrating our results are constructed. It is shown that with certain caveats fixed point theorem for additive-type mappings is equivalent to the fixed point theorem for perturbed metric spaces, which were recently introduced by M. Jleli and B. Samet.

2606.07022 2026-06-08 math.ST stat.TH 新提交

Integral stochastic orders of $m$-generalized order statistics from transform-ordered nonparametric families

来自变换有序非参数族的 $m$-广义次序统计量的积分随机序

Idir Arab, Tommaso Lando, Paulo Eduardo Oliveira, Tomasz Rychlik

AI总结 本文为 $m$-广义次序统计量在递增凹、递增凸和星形随机序下提供比较的充分条件,涵盖经典次序统计量、删失II型次序统计量和记录值,并采用非参数变换有序假设。

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AI中文摘要

我们提供了关于递增凹、递增凸和星形随机序下比较 $m$-广义次序统计量的充分条件。这些条件允许我们对经典次序统计量、选定的删失II型次序统计量和记录值进行排序。它们依赖于广义次序统计量的参数和潜在分布。我们采用非参数方法,假设某种随机变换有序性质,即某种合适的形状条件,而不是假设特定的参数形式。这个框架涵盖了许多通过变换序与广义和负广义帕累托分布相关的相关分布类。

英文摘要

We provide sufficient conditions for comparing $m$-generalized order statistics with respect to the increasing concave, increasing convex, and star-shaped stochastic orders. These conditions allow us to rank classical order statistics, selected censored type-II order statistics, and records. They depend on both the parameters of the generalized order statistics and the underlying distribution. Rather than assuming a specific parametric form, we adopt a nonparametric approach and assume some stochastic transform-ordered property, that is, some suitable shape condition. This framework encompasses many relevant classes of distributions that are related, via transform order, to the generalized and the negative generalized Pareto distribution.

2606.07021 2026-06-08 math.AP 新提交

Rogue waves for semilinear wave equations

半线性波动方程的流氓波

Julia Henninger

AI总结 通过变分方法,研究半线性波动方程在空间和时间上局部化的解(流氓波)的存在性,给出系数和椭圆算子的充分条件。

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AI中文摘要

我们研究在 $\mathbb{R}^N \times \mathbb{R}$ 上的半线性波动方程 $ V(x) \partial_t^2 u + d(t) M(x,\nabla_x) u=\tilde{V}(x) \tilde{d}(t) |u|^{p-1}u$,并通过变分方法证明存在空间和时间上局部化的解,称为流氓波。我们在合适的 Hilbert 空间上引入能量泛函,并给出系数 $V, \tilde{V}, d, \tilde{d}$、椭圆算子 $M$ 和 $p>1$ 的充分条件以确保临界点的存在。我们的方法基于对波动型算子的详细分析,特别是其谱性质。进一步的 regularity 考虑表明临界点是方程的弱解。此外,我们给出了满足假设的系数和椭圆算子的例子。

英文摘要

We study the semilinear wave equation $ V(x) \partial_t^2 u + d(t) M(x,\nabla_x) u=\tilde{V}(x) \tilde{d}(t) |u|^{p-1}u$ on $ \mathbb{R}^N \times \mathbb{R}$ and show the existence of solutions which are localized in space and in time, called rogue waves, by means of variational methods. We introduce an energy functional on a suitable Hilbert space, and provide sufficient conditions on the coefficients $V, \tilde{V}, d, \tilde{d}$, the elliptic operator $M$ and $p>1$ for the existence of a critical point. Our approach is based on a detailed analysis of the wave type operator and in particular its spectral properties. Further regularity considerations show that critical points are weak solutions to our equation. Moreover, we provide examples of the coefficients and the elliptic operator which satisfy our assumptions.

2606.07010 2026-06-08 math.AP 新提交

Gauge transforms, random averaging operator ansatz and improved probabilistic well-posedness for the radial NLS on the $3d$ ball

规范变换、随机平均算子ansatz及三维球上径向NLS的改进概率适定性

Nicolas Burq, Nicolas Camps, Chenmin Sun, Nikolay Tzvetkov

AI总结 通过不修改方程的规范变换和随机平均算子的精细调制分析,改进了Bourgain-Bulut的结果,在超临界概率尺度下构造了三维球上径向三次薛定谔方程的概率强解。

Comments 75 pages,

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AI中文摘要

我们在三维球上构造了具有径向初始数据的立方薛定谔方程的概率强解,这是对Bourgain--Bulut结果的显著改进。这些解相对于Deng--Nahmod--Yue引入的概率尺度处于超临界状态。我们通过不修改方程的规范变换,结合使用随机平均算子的精细调制分析,实现了这一结果。

英文摘要

We construct probabilistic strong solutions to the cubic Schrödinger equation on the three-dimensional ball with radial initial data, which is a significant improvement of a result by Bourgain--Bulut. These solutions lie in the supercritical regime with respect to the probabilistic scaling introduced by Deng--Nahmod--Yue. We achieve this result through gauge transformations that do not modify the equation, combined with a refined modulation analysis using random averaging operators.

2606.07004 2026-06-08 math.NA cs.NA 新提交

Optimal Stochastic Krylov based Techniques for Large- Scale Log-Determinant Estimation

基于最优随机Krylov的大规模对数行列式估计技术

Verlon Roel Mbingui, Antoine Tambue, Issa Karambal

AI总结 提出两种高效大规模对数行列式估计方法:OSA-IOP和OSLQ,分别结合不完全正交化与随机Hutch++算法、Lanczos求积与受控正交化,理论推导误差界,实验验证精度与可扩展性。

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AI中文摘要

估计大型稀疏正定对称矩阵的行列式的对数,是数值线性代数、机器学习、高斯过程和不确定性量化中的重要任务。本文介绍了两种可扩展且高效的大规模对数行列式估计方法,称为最优随机Arnoldi不完全正交化过程(OSA-IOP)和最优随机Lanczos求积(OSLQ)。OSA-IOP方法将最初为指数时间步进积分器中的矩阵指数函数开发的不完全正交化过程(IOP)扩展到计算矩阵算法对向量的作用。我们观察到,将IOP与随机Hutch++算法结合,OSA-IOP显著降低了计算成本,同时保持高精度。OSLQ方法通过将Lanczos求积与Hutch++和受控正交化相结合来估计对数行列式,利用Krylov子空间作为有效的求积机制来逼近涉及矩阵对数的二次型。我们推导了两种方法的误差界。对来自实际应用的大规模稀疏矩阵进行的大量数值实验证明了所提出方法的准确性、鲁棒性和可扩展性。

英文摘要

Estimating the logarithm of the determinant of large sparse positive definite symmetric matrices is an important task in numerical linear algebra, machine learning, Gaussian processes, and uncertainty quantification. In this work, we introduce two scalable and efficient methods for large-scale log-determinant termed the Optimal Stochastic Arnoldi with Incomplete Orthogonalization Procedure (OSA-IOP) and the Optimal Stochastic Lanczos Quadrature (OSLQ). The OSA-IOP approach extends the Incomplete Orthogonalization Procedure (IOP), originally developed for matrix exponential functions for exponential time stepping integrators, to compute the action of the matrix algorithm on a vector. We observe that combining IOP with a randomized Hutch++ algorithm, the OSA-IOP significantly reduces computational cost while maintaining high accuracy. The OSLQ method estimates log-determinants by coupling Lanczos quadrature with Hutch++ and controlled orthogonalization, leveraging Krylov subspaces as efficient quadrature mechanisms to approximate quadratic forms involving the matrix logarithm. We derive error bounds for both methods. Extensive numerical experiments on large-scale sparse matrices from real-world applications demonstrate the accuracy, robustness, and scalability of the proposed approaches.

2606.07003 2026-06-08 math.OC 新提交

A Single-Loop Regularized Newton Method for Nonconvex-Strongly-Concave Minimax Optimization

非凸-强凹极小极大优化的单循环正则化牛顿方法

Bohao Ma, Nachuan Xiao, Junyu Zhang

AI总结 针对光滑非凸-强凹极小极大问题,提出一种基于等价正则化最小化重构的单循环框架,通过自适应三次-二次主化处理非Lipschitz Hessian分量,实现全局复杂度匹配双循环二阶方法,并自动获得局部超线性收敛率。

Comments 29 pages

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AI中文摘要

对于光滑非凸-强凹极小极大问题,现有的二阶方法共享一个共同的双循环结构,其中内部最大化问题在每次二阶步骤之前被求解到足够高的精度。为了可扩展性,内循环通常采用一阶方法,但这削弱了二阶方法对条件数不敏感的特性,将这些方法限制在条件温和的实例上。为解决此问题,我们提出了一种新颖的单循环框架,该框架基于原始问题的等价正则化最小化重构。通过推导一种新的自适应三次-二次主化来动态吸收重构Hessian的非Lipschitz分量,我们建立了一种正则化牛顿方法,在多种设置下具有稳健的理论保证。对于确定性问题,我们的单循环方法匹配了现有双循环二阶方法的$\mathcal{O}(\varepsilon^{-1.5})$全局迭代复杂度,同时自动实现了局部超线性收敛速度,而由于内循环瓶颈,现有工作中无法实现此速度。对于随机设置,通过集成递归方差缩减,我们实现了$\mathcal{O}(\varepsilon^{-3})$梯度和$\mathcal{O}(\varepsilon^{-2})$ Hessian复杂度,严格比双循环方法提升了$\mathcal{O}(\varepsilon^{-0.5})$因子。在确定性和随机实验中,我们的方法显著优于基准方法,即使在条件温和的实例下也比双循环方法提供了大幅加速。作为我们分析的副产品,我们填补了非凸最小化随机二阶方法中的一个空白,其中已知最佳结果存在一个非平凡的技术问题。

英文摘要

For smooth nonconvex-strongly-concave minimax problems, existing second-order methods share a common double-loop structure where the inner maximization is solved to sufficiently high accuracy before each second-order step. First-order methods are often adopted in the inner loops for scalability, but they also undermine the condition-insensitivity of second-order methods, limiting these methods to instances with mild conditioning. To resolve this issue, we propose a novel single-loop framework based on an equivalent regularized minimization reformulation of the original problem. By deriving a new adaptive cubic-quadratic majorization to dynamically absorb the non-Lipschitz components of the reformulated Hessian, we establish a regularized Newton method with robust theoretical guarantees across multiple settings. For deterministic problems, our single-loop method matches the $\mathcal{O}(\varepsilon^{-1.5})$ global iteration complexity of the existing double-loop second-order methods, while automatically achieving a local superlinear rate that is unavailable in existing works due to the inner-loop bottleneck. For the stochastic setting, we achieve $\mathcal{O}(\varepsilon^{-3})$ gradient and $\mathcal{O}(\varepsilon^{-2})$ Hessian complexities by integrating a recursive variance reduction, strictly improving those of the double-loop methods by $\mathcal{O}(\varepsilon^{-0.5})$ factors. In both deterministic and stochastic experiments, our methods significantly outperform the benchmarks, offering substantial speedups over the double-loop methods even under mildly conditioned instances. As a byproduct of our analysis, we close a gap in stochastic second-order methods for nonconvex minimization, where the best known result contains a nontrivial technical issue.

2606.06993 2026-06-08 math.NT 新提交

A mod $p$ determinant criterion for Cohen--Lenstra convergence of random $p$-adic matrices with prescribed zero patterns

具有指定零模式的随机 $p$-adic 矩阵的 Cohen--Lenstra 收敛性的模 $p$ 行列式判据

Hyungmin Jang, Nathan Kaplan, Jungin Lee, Myungjun Yu

AI总结 受 Cohen--Lenstra 启发,研究具有指定零模式的 Haar 随机 $p$-adic 矩阵的余核分布,证明其收敛于 Cohen--Lenstra 分布等价于模 $p$ 的渐近非奇异性条件。

Comments 15 pages

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AI中文摘要

我们研究具有指定零模式的 $p$-adic 整数上 Haar 随机矩阵的余核分布,受 Cohen--Lenstra 启发。我们方法的一个核心特征是,渐近余核分布由这些矩阵模 $p$ 的约化(视为有限域 $\mathbb{F}_p$ 上的随机矩阵)所控制。对于由阶梯形零区域产生的几种支撑模式族,包括一般阶梯形模式、带状矩阵和具有两个对称阶梯形零区域的矩阵,我们证明余核分布收敛于 Cohen--Lenstra 分布等价于 $\mathbb{F}_p$ 上的渐近非奇异性条件。我们进一步对一般支撑模式提出一个猜想,并给出例子表明对于 $r\ge 1$,类似的秩 $r$ 判据不成立。

英文摘要

We study the distribution of cokernels of Haar-random matrices over the $p$-adic integers with prescribed zero patterns, motivated by the Cohen--Lenstra heuristics. A central feature of our approach is that the asymptotic cokernel distribution is governed by the reductions modulo $p$ of these matrices, viewed as random matrices over the finite field $\mathbb{F}_p$. For several families of support patterns arising from stair-shaped zero regions, including general stair-shaped patterns, band matrices, and matrices with two symmetric stair-shaped zero regions, we show that convergence of the cokernel distribution to the Cohen--Lenstra distribution is equivalent to an asymptotic nonsingularity condition over $\mathbb{F}_p$. We further propose a conjecture for general support patterns and give examples showing that analogous rank-$r$ criteria fail for $r\ge 1$.

2606.06987 2026-06-08 math.CO 新提交

Tight Bound for Nikiforov's Spectral Even-Cycle Conjecture

Nikiforov谱偶环猜想的紧界

Peiru Kuang, Feng Liu, Shuang Sun, Yan Wang, Jiasheng Zeng

AI总结 针对Nikiforov关于不含偶环图谱半径极值的猜想,证明了对所有α<1,当n≥Ck时,唯一极图是S^+_{n,k},且阈值线性于k,解决了Li和Ning提出的指数问题。

Comments 21 pages, comments are welcome

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AI中文摘要

Nikiforov猜想:对于每个固定的$k\ge2$和所有足够大的$n$,唯一具有最大邻接谱半径的$n$顶点$C_{2k+2}$-自由图是$S^+_{n,k}$,其中$S_{n,k}=K_k\vee\overline K_{n-k}$,而$S^+_{n,k}$是通过在独立部分内添加一条边从$S_{n,k}$得到的。Cioabă、Desai和Tait证明了该猜想对$n\ge k^{O(k)}$成立。后来,Li和Ning提出了确定最优指数$\gamma=\gamma(k)$的问题,使得相同的结论对$n\ge \Omega(k^{\gamma(k)})$成立。我们证明了Nikiforov矩阵$A_\alpha(G)=\alpha D(G)+(1-\alpha)A(G)$的一个更强的统一定理。更精确地说,对于每个$\epsilon>0$,存在常数$C_\epsilon$和$k_\epsilon$,使得对所有$0\le\alpha\le1-\epsilon$、$k\ge k_\epsilon$和$n\ge C_\epsilon k$,每个$n$顶点$C_{2k+2}$-自由图$G$满足$\rho_\alpha(G)\le\rho_\alpha(S^+_{n,k})$,等式成立当且仅当$G\cong S^+_{n,k}$。特别地,$\alpha=0$的情形在线性范围内回答了Li和Ning的问题,并且$A_\alpha$-谱偶环阈值关于$k$是线性的,对所有远离$1$的$\alpha$一致成立。我们的证明引入了一个带权有根的Erdős--Gallai型路径引理,该引理在谱极值图问题的Perron向量方法中可能具有独立意义。同样的方法还为两个局部禁止子图族,即$(K_1\vee P_\ell)$-自由图和$F_s$-自由图(其中$F_s$表示友谊图),给出了渐近紧的$A_\alpha$-谱界。

英文摘要

Nikiforov conjectured that, for every fixed $k\ge2$ and all sufficiently large $n$, the unique $n$-vertex $C_{2k+2}$-free graph with maximum adjacency spectral radius is $S^+_{n,k}$, where $S_{n,k}=K_k\vee\overline K_{n-k}$ and $S^+_{n,k}$ is obtained from $S_{n,k}$ by adding one edge inside the independent part. Cioabă, Desai and Tait proved this conjecture for $n\ge k^{O(k)}$. Later, Li and Ning raised the problem of determining the optimal exponent $γ=γ(k)$ such that the same conclusion holds for $n\ge Ω(k^{γ(k)})$. We prove a stronger uniform theorem for Nikiforov's matrices $A_α(G)=αD(G)+(1-α)A(G)$. More precisely, for every $ε>0$ there are constants $C_ε$ and $k_ε$ such that for all $0\leα\le1-ε$, $k\ge k_ε$ and $n\ge C_εk$, every $n$-vertex $C_{2k+2}$-free graph $G$ satisfies $ρ_α(G)\leρ_α(S^+_{n,k})$, with equality if and only if $G\cong S^+_{n,k}$. In particular, the case when $α=0$ answers the problem of Li and Ning in the linear range, and the $A_α$-spectral even-cycle threshold is linear in $k$, uniformly for all $α$ bounded away from $1$. Our proof introduces a weighted rooted Erdős--Gallai type path lemma, which may be of independent interest in Perron-vector methods for spectral extremal graph problems. The same method also yields asymptotically tight $A_α$-spectral bounds for two local forbidden-subgraph families, namely $(K_1\vee P_\ell)$-free graphs and $F_s$-free graphs, where $F_s$ denotes the friendship graph.

2606.06982 2026-06-08 cs.IT math.IT 新提交

Mutual Information Optimization via K-Recursion and Automatic Differentiation for Linear Gaussian Wireless Networks

通过K-递归和自动微分优化线性高斯无线网络的互信息

Tadashi Wadayama, Na Siqi

AI总结 提出一种可微框架,通过K-递归解析传播协方差并利用自动微分计算梯度,在全局约束下优化线性高斯有向无环图的端到端互信息,适用于多种拓扑且无需拓扑特定梯度公式。

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AI中文摘要

我们提出了一种可微框架,用于在线性高斯有向无环图(DAG)上进行端到端互信息(MI)优化。该框架针对全局约束(如总发射功率预算)下的网络级设计,并在一个通用的线性高斯模型中涵盖了MIMO预编码、放大转发中继、RIS辅助信道以及分支/合并拓扑。其核心成分是\emph{K-递归},它沿着DAG按拓扑顺序解析地传播所有节点对协方差,包括正确处理分支和合并路径所需的非相邻交叉协方差。由此产生的协方差给出了端到端MI的闭式对数行列式表达式,作为可控因子的光滑函数。在此K-递归上应用复值反向模式自动微分,则在单次反向扫描中返回每个可控因子处的精确Wirtinger梯度,并使用投影梯度上升(PGA)在全局约束下最大化MI。由于不需要每个拓扑的闭式梯度表达式,相同的拓扑无关实现适用于任何线性高斯DAG。一个拓扑无关的实现被应用于四类代表性DAG:单链路MIMO、菱形DAG、两跳AF中继和输入协方差整形。相同的实现在可用设置中达到了经典注水最优,并在非单链路拓扑中实现了MI改进,而无需使用拓扑特定的梯度公式。在一个多层高斯网络(11个节点,5层)上的进一步实验说明了其对没有闭式梯度的非平凡多层拓扑的适用性。

英文摘要

We present a differentiable framework for end-to-end mutual information (MI) optimization over linear Gaussian directed acyclic graphs (DAGs). The framework targets network-wide design under global constraints, such as a total transmit power budget, and covers MIMO precoding, amplify-and-forward relays, RIS-aided channels, and branching/merging topologies within a common linear Gaussian model. Its core ingredient is a \emph{K-recursion} that analytically propagates all node-pair covariances along the DAG in topological order, including non-adjacent cross-covariances that are necessary for correctly handling branching and merging paths. The resulting covariances yield a closed-form log-determinant expression for the end-to-end MI as a smooth function of the controllable factors. Complex-valued reverse-mode automatic differentiation on this K-recursion then returns the exact Wirtinger gradient at every controllable factor in a single backward sweep, and projected gradient ascent (PGA) is used to maximize the MI under the global constraints. Because no closed-form gradient expression per topology is required, the same topology-agnostic implementation applies to any linear Gaussian DAG. A single topology-agnostic implementation is applied to four representative DAG classes: single-link MIMO, a diamond DAG, a two-hop AF relay, and input-covariance shaping. The same implementation reaches the classical water-filling optimum in the settings where it is available and yields MI improvements in non-single-link topologies without using topology-specific gradient formulas. A further experiment on a multi-layer Gaussian network (11 nodes, 5 layers) illustrates applicability to nontrivial multi-layer topologies for which no closed-form gradient is available.

2606.06965 2026-06-08 math.CO math.CA math.MG 新提交

Visible parts and lower bounds on point-ray incidences

可见部分与点射线关联的下界

Tuomas Orponen, Alex Rutar

AI总结 研究平面紧集在几乎所有方向上的可见部分的Hausdorff维数,利用改进的射线关联下界定理,将上界从11/6改进到3/2。

Comments 30 pages

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AI中文摘要

设 $K \subset \mathbb{R}^{2}$ 为紧集。对于 $\theta \in S^{1}$,令 $\mathrm{Vis}_{\theta}(K) \subset K$ 为 $K$ 在方向 $\theta$ 上的可见部分。我们证明对于 $\mathcal{H}^{1}$ 几乎所有的 $\theta \in S^{1}$,有 $\operatorname{dim}_{\mathrm{H}} \mathrm{Vis}_{\theta}(K) \leq \tfrac{3}{2}$。之前的记录是 $\operatorname{dim}_{\mathrm{H}}\mathrm{Vis}_{\theta}(K) \leq 11/6 \approx 1.833$,由 D. Dąbrowski 得到。我们的主要工具是 Cohen、Pohoata 和 Zakharov 最近的一个关联下界定理的变体,其中粗略地说,直线被替换为射线,$\delta^{\varepsilon}$-分离的关联被替换为 $1$-分离的关联。

英文摘要

Let $K \subset \mathbb{R}^{2}$ be a compact set. For $θ\in S^{1}$, let $\mathrm{Vis}_θ(K) \subset K$ be the visible part of $K$ in direction $θ$. We prove that $\operatorname{dim}_{\mathrm{H}} \mathrm{Vis}_θ(K) \leq \tfrac{3}{2}$ for $\mathcal{H}^{1}$ almost every $θ\in S^{1}$. The previous record was $\operatorname{dim}_{\mathrm{H}}\mathrm{Vis}_θ(K) \leq 11/6 \approx 1.833$, due to D. Dąbrowski. Our main tool is a variant of a recent incidence lower bound theorem due to Cohen, Pohoata, and Zakharov where, roughly speaking, lines have been replaced by rays, and $δ^{\varepsilon}$-separated incidences are replaced by $1$-separated incidences.

2606.06964 2026-06-08 math.RT 新提交

Widths of regular components for n-regular tree $T(n)$

n-正则树 $T(n)$ 的正则分支的宽度

Jie Liu

AI总结 研究广义Kronecker箭图覆盖的正则Auslander-Reiten分支的宽度与流模数,证明宽度不小于(流模数+1)/2,且所有正则分支的宽度构成自然数集。

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AI中文摘要

设 $(T(n),\Omega)$ 是广义 Kronecker 箭图 $K(n)$ 的覆盖,其中 $\Omega$ 是一个二分定向。给定 $\modd(T(n),\Omega)$ 的一个正则 Auslander--Reiten 分支 $\cD$,我们引入两个不变量:宽度 $\cW(\cD)$ 和流模数 $b(\cD)$。我们证明 $\cW(\cD)\geq \frac{b(\cD)+1}{2}$。特别地,我们得到 $\{\cW(\cD)| \cD \text{ 是正则分支}\}=\mathbb{N}$。

英文摘要

Let $(T(n),Ω)$ be the covering of the generalized Kronecker quiver $K(n)$, where $Ω$ is a bipartite orientation. Given a regular Auslander--Reiten component $\cD$ of $\modd(T(n),Ω)$, we introduce two invariants: the width $\cW(\cD)$ and the number of flow modules $b(\cD)$. We show that $\cW(\cD)\geq \frac{b(\cD)+1}{2}$. In particular, we get $\{\cW(\cD)| \cD \text{ is a regular component} \}=\mathbb{N}$.

2606.06956 2026-06-08 math.AP 新提交

Thermal Relaxation Effects on Stability Thresholds: A Comparative Analysis of Thermoelastic Timoshenko-Boltzmann Systems Under Fourier and Cattaneo Laws

热弛豫效应对稳定性阈值的影响:傅里叶和卡塔尼奥定律下热弹性Timoshenko-Boltzmann系统的比较分析

Zhou Jun, Mou SiRuo

AI总结 通过半群理论和谱分析,比较了傅里叶抛物型与卡塔尼奥双曲型热传导下具有记忆的热弹性Timoshenko-Boltzmann系统的稳定性,揭示了热弛豫改变指数稳定条件但保持多项式衰减。

Comments 36 pages, 0 figures

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AI中文摘要

本文探讨了具有记忆的热弹性Timoshenko-Boltzmann系统的稳定性二分法,通过半群理论和谱分析比较了傅里叶抛物型(无热弛豫)和卡塔尼奥双曲型(有热弛豫)热传导。傅里叶半群通过δ-条件加上特定参数条件实现指数稳定性,而仅δ-条件保证1/2阶多项式稳定性。卡塔尼奥半群保留了这种多项式稳定性,但需要包含热弛豫的修正参数条件来实现指数稳定性。当热弛豫时间趋近于零时,卡塔尼奥的修正参数收敛于傅里叶的参数,形式化了它们的渐近联系。结果表明,热弛豫改变了指数稳定判据,但保持了多项式衰减,支持了结构力学中随时间变化的热载荷下的稳定性分析。

英文摘要

This paper explores stability dichotomies of thermoelastic Timoshenko-Boltzmann systems with hereditary memory, comparing Fourier's parabolic (no thermal relaxation) and Cattaneo's hyperbolic (with thermal relaxation) heat conduction via semigroup theory and spectral analysis. The Fourier-semigroup achieves exponential stability through the $δ$-condition plus a specific parameter condition, while sole $δ$-condition ensures $1/2$-order polynomial stability. The Cattaneo-semigroup retains this polynomial stability but requires a thermal relaxation-included modified parameter condition for exponential stability. As thermal relaxation time approaches zero, Cattaneo's modified parameter converges to Fourier's, formalizing their asymptotic connection. Results show thermal relaxation alters exponential criteria but preserves polynomial decay, supporting stability analysis under time-dependent thermal loading in structural mechanics.